Ubuntu: My ubuntu partition was deleted and I can't boot from either a DVD or USB

Question:

It's my first time installing ubuntu. I have Windows 7 and 8 before in my laptop (Acer Aspire 4752z). After Ubuntu (12.04) installed in my laptop, the Windows boot loader didn't recognize my Ubuntu so I updated grub from a live USB.

And after grub updated, Ubuntu was booting perfectly but my Windows wasn't listed in the grub menu. So I follow someone instruction to update grub again. And after reboot, the grub menu didn't show anymore.

After searching about this problem on the net and trying to update grub again and again, I decided to delete the Ubuntu partition from live USB. And shortly after, I booted to Windows with Hiren boot and I used mbrfix. But i think it failed. Now i cant show my BIOS setup or boot from DVD or USB.

After that, the only screen i can see after booting is:

error: unknown filesystem grub rescue>

Solution:1

The code that fits in the Drive MBR is very small. In the case of Windows, the bootloader is very simple and merely redirects to the bootsector of the partition with the boot flag set. Grub is a more complicated bootloader, but it's still limited by the space, so it has to load modules from a specific partition (the Ubuntu partition you deleted).

When Grub cannot find those modules (because the partition no longer exists), then you get a very limited grub rescue prompt. It can be used to load grub modules manually, but of course in your case, that's not possible because there is no partition. So there is really nothing you can do (that I am aware of) that will boot the remaining operating system (Windows).

In your case, the simplest way to fix it is to replace the Grub bootloader with a Windows bootloader. You mentioned you have problems booting from DVD and USB, in which case you'll have to figure that out or consider removing your drive to another machine. I think it's pretty unusual for a machine to no longer boot from USB or CD/DVD so I'd try troubleshooting that.

Then you can install the Windows bootloader from a Windows repair prompt (either by booting a Windows repair CD or a Windows Installation DVD) and running:

bootrec /fixmbr

Or you could boot an Ubuntu CD and install a bootloader with equivalent function...